The system has been in operation for six months.

　　這個系統(tǒng)已經運行六個月了。

　　The operation could prolong his life by two or three years.

　　這次手術可使他多活兩三年。

　　His quality of life has improved dramatically since the operation.

　　手術后他的生活質量大大改善了。

　　The new rules come into operation from next week.

　　新規(guī)定從下周起實施。

　　Will I need to have an operation?

　　我需要動手術嗎？